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211.
含偶氮苯的咔唑类双功能光折变聚合物的合成及表征 总被引:1,自引:1,他引:1
通过后重氮偶合方法制备了一系列不同生色团含量的咔唑类双功能光折变聚合物,并用IR、^1H-NMR、UV-vis、DSC以及GPC等对聚合物进行了分析和表征。IR和UV-vis谱图显示偶氮苯基团已接到咔唑环上。UV-vis结果表明:反应时间对该反应的影响非常大,当反应时间从6h增加到60h时,聚合物中生色团的含量从13.5%升高到66.7%。GPC结果显示后重氮偶合法比常规方法得到的该类聚合物的分子量明显提高。DSC结果显示聚合物的玻璃化转变温度随偶氮苯含量的增加而升高。 相似文献
212.
Kubo T Hosoya K Nomachi M Tanaka N Kaya K 《Analytical and bioanalytical chemistry》2005,382(7):1698-1701
A molecularly imprinted polymer was prepared using a water-soluble crosslinking agent. An ionic complex was utilized as the assembly for the template molecule and the functional monomer, and water as porogenic solvent during preparation of the imprinted polymer. The results of chromatographic evaluations for the prepared polymer suggested that the polymer had much lower hydrophobicity compared with usual octadecyl group bonded silica or the usual molecular imprinted polymer prepared from ethyleneglycol dimethacrylate, and the selective recognition ability for template molecule in the completely aqueous condition. 相似文献
213.
Polyethylene based composites are attractive materials for advanced circuit board applications because of their unique combination of properties: low dielectric constant and loss factor, light weight, high flexural modulus and low thermal expansion coefficient controlled in all spatial directions. This investigation describes a process to consolidate chopped fibers of ultra‐high molecular weight polyethylene concurrently with its bonding to a copper foil. Bonding is affected by a thin sheet of low‐density polyethylene, incorporating a crosslinking agent with a concentration gradient across the sheets thickness. In this single step process, the composite material is formed and bonded to the metal foil, achieving good adhesion without the use of extraneous glue. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
214.
Summary A porous polymer resin loaded with hydrous zirconium oxide (Zr-gel) was evaluated as a stationary phase for the liquid chromatographic separation of disubstituted aromatic compounds. The prepared Zr-gel was used to separate disubstituted phenols andortho-substituted benzoic acid derivatives in reversed-phase mode. The retention time of catechol was greater than those of other disubstituted phenols; this implies that the Zr-gel has specificity for the phenolic hydroxyl group. The retention behavior ofortho-substituted benzoic acid derivatives on the Zr-gel was also evaluated in reversedphase mode using buffer. Phthalic acid was specifically retained in the vicinity of pH 6.0, which has been regarded as the equal adsorbic point. Similar behavior was also observed for salicylic acid, although the retention time of salicylic acid was less than that of phthalic acid. It seems that the specific retention behavior of hydrous zirconium oxide is a result of complexation with ligands such as hydroxyl and carboxyl groups. The results of this study have revealed that the retention mechanism of hydrous zirconium oxide is a combination of ion exchange and interaction based on complexation with ligands. 相似文献
215.
Ugo Caruso Antonella De Maria Barbara Panunzi Antonio Roviello 《Journal of polymer science. Part A, Polymer chemistry》2002,40(17):2987-2993
Two formulas of grafted polymers with metal‐containing chromophores, potentially suitable for second‐order nonlinear optics applications, are described. Two chromophores were obtained from a tridentate ligand coordinated to Cu(II) or Pd(II) ions. The organometallic chromophore fragments were grafted to poly(4‐vinylpyridine) by the pyridinic nitrogen of the host polymer. Some qualities displayed by the new metallated polymers are remarkable: (1) a high value of the first hyperpolarizability coefficient of the chromophores, (2) a high content of the grafted chromophore in the polymers (up to 60 wt %), (3) a considerable increase in the glass‐transition temperatures (up to 240 °C), (4) good thermal stability in air (ca. 280 °C), and (5) good optical transparency of the films. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2987–2993, 2002 相似文献
216.
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218.
XI Jingyu QIU Xinping ZHU Wentao & CHEN Liquan Department of Chemistry Tsinghua University Beijing China 《中国科学B辑(英文版)》2005,48(6)
All solid-state lithium polymer batteries may be one of the best choices for the future electrochemical power source, characterized by high energy densities, good cyclability, reliability and safety[1,2]. Owing to its potential capability to replace the t… 相似文献
219.
A star network polymer with a pentaerythritol core linking four PEG-block polymeric arms was synthesized, and its corresponding gel polymer electrolyte based on lithium perchlorate and plasticizers EC/PC with the character being colorless and highly transparent has been also prepared. The polymer host was characterized and confirmed to be of a star network and an amorphous structure by FTIR, ^1H NMR and XRD studies. The polymer host hold good mechanical properties for pentaerythritol cross-linking. Maximum ionic conductivity of the prepared polymer electrolyte has reached 8.83 × 10 ^-4 S·cm^-1 at room temperature. Thermogravimetry (TG) of the polymer electrolyte showed that the thermal stability was up to at least 150 ℃. The gel polymer electrolyte was further evaluated in electrochromic devices fabricated by transparent PET-ITO and electrochromically active viologen derivative films, and its excellent performance promised the usage of the gel polymer electrolyte as ionic conductor material in electrochrornic devices. 相似文献
220.
Noble metal nanoparticles were prepared by the in situ reduction of the respective metal salt precursors in the presence
of various protective polymers. Transmission electron microscopy (TEM) has been used to determine the particle shapes and
morphologies. These are strongly influenced by the reduction methods and conditions chosen, but the choice of the protective
polymer is equally important for controlling the particle morphologies and for the stabilization of the colloids. A whole
spectrum of nanoparticle morphologies and shapes was obtained, ranging from nanoagglomerates which are nevertheless well-defined
and well-stabilized to nanosized single crystals with triangular shape.
Received: 2 February 1998 Accepted: 29 May 1998 相似文献